Conversion of hydrocarbons



.Fuy Z, 1946. R. B. DAY

CONVERSION oF HYDRocARBoNs Filed Feb. ll, 1944 Patented July 2, 1,946

CONVERSIGN OF HYDROCARBONS Roland B. Day, Riverside, Ill., assigner to Universal Oil Products Company, Chicago, Ill., a

corporation of Delaware Application February 1l, 1944, Serial N o. 521,929

2 Claims.

This invention relates to the conversion of hydrocarbons and more particularly to a process for reacting an alkylatable parainic hydrocarbon with an olenic hydrocarbon and concurrently therewith isomerizing a higher boiling, normally liquid parailinic hydrocarbon.

In a broad aspect the present invention relates to a hydrocarbon conversion process which comprises reacting an alkylatable parainic hydrocarbon with an olei'lnic hydrocarbon in the presence of a catalyst having alkylating and isomerizing properties and simultaneously isomerizing an isomerizable paraflinic hydrocarbon of less branching and of a greater number of carbon atoms per molecule than said allrylatable para-inic hydrocarbon.

In one specific embodiment the present invention relates to a hydrocarbon conversion process which comprises alkylating isobutane with ethylene and concurrently therewith isomerizing a pentane-hexane fraction of straight run gasoline in the presence of a catalyst having alkylating and isomerizing properties and a catalyst promoter at a temperature of from about 100 to about 350 F.

In accordance with the invention, an alkylatable paranic hydrocarbon, which may comprise an isoparainic hydrocarbon and particularly isobutane or isopentane, is reacted with an olenic hydrocarbon, which may be either normally gaseous and thus may comprise ethylene, propylene or butylene, or normally liquid, such as amylenes, heXenes, oleiinic polymers, etc. The process is particularly applicable to the allylation of isobutane by ethylene in order to produce branched chain hexane and particularly 2,3-dimethylbutane.

Concurrently with the reaction of the isoparaffinic and olenic hydrocarbons, an isomerizable parafnic hydrocarbon which is of less branching than said isoparafnic hydrocarbon and which contains a greater number of carbon atoms per molecule, is subjected to isomerization. In this Way, straight or mildly branched parafnic hydrocarbons are converted into more highly branched paraflinic hydrocarbons. Thus, selec-ted fractions of straight run gasolines, such as those containing normal pentane, hexane, heptane, octane, etc., or mixtures thereof, may be reformed into high octane saturated gasoline fractions which are particularly suitable for use in aviation gasoline.

Any suitable catalyst having alkylating and isomerizing properties may be employed and thus may comprise a metal halide catalyst of the Friedel-Crafts type o-r mixtures thereof and preferably aluminum chloride. The metal halide catalysts are normally employed in conjunction with a catalyst promoter which usually comprises a hydrogen halide or a halogen compound which functions as a catalyst promoter under the conditions of treatment. When using aluminum chloride catalyst, hydrogen chloride is normally introduced as the catalyst promoter and either functions as such or is converted into an alkyl chloride which acts accordingly. For example, in the alkylation of isobutane with ethylene, it has been found that the ethylene reacts with the hydrogen chloride to form ethyl chloride and that the ethyl chloride satisfactorily functions as a catalyst promoter. Another suitable catalyst may comprise a mixture of boron fluoride and hydrogen fluoride.

The process of the present invention may be effected at a temperature within the range of from about to about 350 F. and preferably within the range of from about to about 300 F. It is preferred that a substantial proportion of the reactants are in liquid phase and sufficient pressure should therefore be utilized in order to accomplish this. The pressure thus may range from about 50 to 500 pounds or more and preferably is Within the range of from about 200 to about 400 pounds. The temperature and pressure conditions herein set forth are satisfactory for the alkylation of isobutane or isopentane with ethylene, propylene and/or butylene and the simultaneous isomerlzation of pentane, hexane, heptane and/or octane in the presence of aluminum chloride catalyst in conjunction with hydrogen chloride. It is understood, however, that the broad scope of the present invention is not so limited, and that the conditions of operation may have to be modified When different charging stocks are employed and also when other catalysts are utilized. The other metal halide catalysts of the Friedel-Crafts type are usually less active than aluminum chloride and in general will require more severe conditions of treatment.

The present invention may be eected in any suitable type of apparatus in which the reactants are intimately contacted with the catalyst under the desired conditions of treatment. One suitable method is illustrated in the accompanying flow diagram, but it is understood that the broad scope of the invention is not limited to this particular method of operation.

In the interest of simplicity, the following description will be restricted to a process for the alkylation of isobutane with ethylene and the isomerization cf a pentane-hexane fraction of straight run gasoline in the presence of an aluminum chloride catalyst in conjunction with hydrogen chloride.

Referring to the drawing, isobutane may be introduced to the process at the desired tein- .perature and pressurathrough line I and valve 2' into catalyst pick-up Zone 3. Zone 3 contains a bulk Supply of aluminum chloride and a regulated portion thereof is carried over with the isobutane and withdrawn from the upper portion of Zone 3 through line il containing valve 5. Hydrogen chloride may be introduced through line containing valve l, while the pentane-hexane fraction may be introduced through line 8 containing valve 9, and ethylene may be introduced through line Il) containing valve II. The amount of hydrogen chloride so introduced will usually be about l to about 15%. rIhe ethylene will usually be contained in admixture with ethane, but the amount of oleiins so introduced will usually be of the order of to 25% of the isobutane introduced to the reaction zone, so that there will be an excess of isoparains present in the reaction zone to thereby minimize undesirable polymerization reactions. The reactants are directed by way or" line 4 into reactor I2. It is understood that the hydrogen chloride, ethylene or pentane-hexane fraction may be introduced to reactor I2 in any other suitable method and also, when desired, that the pentane-hexane fraction may be utilized to piel; up and carry the catalyst from zone 3 into reactor IZ, in which case the isobutane may be supplied directly to reactor I2 by well known means not illustrated.

As another advantage of the present process, any olenic hydrocarbons which may be contained in the pentane-hexane fraction will react with the isobutane or other isoparalinic hydrocarbons present in this zone, and thereby will produce a final product which is substantially free of olenic hydrocarbons and will be particularly suitable for use in aviation gasoline. In addition to the reaction of isobutane with ethylene and the isomerization of the pentanehexane fraction, these reactants may also undergo other reactions among themselves so that the final product is highly branched and exceptionally valuable.

In the case here illustrated, reactor I2 cornprises a mechanically agitated zone containing stirring device I3 operated by motor I4. When desired, Zone i2 may be equipped with suitable cooling means, not shown, in order to control the exothermic heat of reaction.

rhe reaction mixture from zone I2 is directed through line I5 containing valve I6 to settler I1, in which a hydrocarbon layer separates from a catalyst layer. The hydrocarbon layer may be withdrawn through line I8 and valve I9 and then is directed to suitable ractionating and separating means, not illustrated, in order to recover the desired products and to separate unconverted fractions for recycling, such as excess isobutane, hydrogen chloride, etc. Since the fractionation and separation equipment is conventional and since no novelty is claimed herein for it per se, it has been omitted from the drawing in the interest of simplicity;

The catalyst layer withdrawn from the lowerY portion of settler I 'I' may be removed from the process, al1 or in part, through line 2l] and valve 2|, but preferably at least a portion thereof is recycled by way of line 22, valve 23, pump 2t, line 25 and valve 25 to reactor I2. A preferred type of operation is the so-called sludge type in which a hydrocarbon-aluminum chloride complex is used as the primary catalyst and, in such an operation, a major portion of the catalyst layer from settler I'l is recycled to reactor I2.

As heretofore set forth, the drawing illustrates one satisfactory method of operation. Another satisfactory, method may comprise an operation in which reactor IZ is packed with a suitable adsorbent material, such as alumina, and the catalyst carried over from Zone 3 is deposited on the packing. Still another operation may use a pool of aluminum chloride introduced into the reactor by any suitable means. In still another operation, a previously prepared solid catalyst may be deposited in the reactor before charging the reactants thereto.

The following example further illustrates the novelty and utility of the present invention but not with the intention of unduly limiting the same.

A charging mixture comprising 40% isobutane, 8% ethylene, 25% of a pentane-hexane fraction, and 4% of hydrogen chloride, the remainder comprising other constituents normalb7 present with the ethylene and isobutane fractions, may be subjected to conversion in the presence of an aluminum chloride catalyst at a temperature of F. and a pressure of about 300 pounds per square inch to produce a nnal product consisting of substantial amounts of 2,3- dimethylbutane, isohexane and Y isopentane. This product will be substantially saturated and of high antiknock properties and, therefore, is particularly suitable for use in aviation gasoline.

I claim as my invention:

1. In the alkylation of iso-butane with ethylene in a reaction zone in the presence of a Friedel- Crafts type catalyst, the improvement Which comprises introducing to said rone simultaneously with the isobutane a normally liquid predominantly paraiiinic straight-run gasoline fraction containing a normal paraiiin of at least 5 carbon atoms to the molecule and therein isomerizing said normal paraihn with the aid of said catalyst during the alkylation of the isobutane, whereby to increase the antilnock value of the straight-run gasoline fraction and form a substantially saturated aviation fuel comprising isomerized and alkylated paraines including 2,3-dime'thylbutane.

2. In the alkylation of isobutane with etheylene in a reaction Zone in the presence of an aluminum chloride catalyst, the improvement which comprises introducing to said Zone simultaneously with the isobutane a normally liquid predominantly parafnic straight-run gasoline fraction containing a normal parain of at least 5 carbon .atoms to the molecule and therein isomerizing said normal parainn with the aid of said catalyst during the alkylation of the isobutane, whereby to increase the antiknock value of the straight-run gasoline fraction and form a substantially saturated aviation fuel comprising isomerized and alkylated paramns including 2,3- dimethylbutane.

ROLAND B. DAY.

but not necessarily equivalent,- 

